1. Field of the Invention
The present invention relates to a hands-free signal processing device in a mobile communication terminal. More particularly, the present invention relates to a hands-free signal processing device in a mobile communication terminal, which may separate hands-free signals, such as a microphone (MIC) signal and an interrupt signal generated in a hands-free device, by using transistors, and properly process the hands-free signals.
2. Description of the Related Art
As distribution of mobile communication terminals such as a celluar phone, an internet phone, IMT-2000 terminal and PDA phone rapidly increases due to development of communication technology, accessories and various supplementary items for such mobile communication terminals are also being developed. One of the accessories and various supplementary items is a hands-free device.
The hands-free device has a lot of shapes and a representative device is an earphone type hands-free device having a function of microphone.
As illustrated in FIG. 1, the earphone type hands-free device comprises an ear-jack 11 for connecting the hands-free device to mobile communication terminals and an earphone 12 for receiving sounds, the ear-jack 11 being an end of the hands-free device, the earphone 12 being another end of the hands-free device. The hands-free device further comprises a microphone 14 for transferring a voice and a talk-key 15 for connecting and disconnecting calls between the ear-jack 11 and the earphone 12. The hands-free device further comprises an earphone wire 13 having a signal line for communicating with mobile communication terminals, the earphone wire 13 connecting the ear-jack 11, the earphone 12, the microphone 14 and the talk-key 15.
In a hands-free device for mobile communication terminals in the related art, an audio signal from the microphone 14 and an interrupt signal generated by pressing the talk-key 15 have the same pattern and the signals transferred through one signal line. Thus, there is a problem in timing that a bug preventing a relevant reaction to the press of a talk-key of a hands-free device could happen. Besides, current consumption is badly increased by using a high level as reference timing.